VisCPT Image Processing, Hardware Modification and Application Development

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

The Vision Cone Penetrometer (VisCPT) is an electronic cone penetrometer containing two miniature CCD video cameras. The cameras collect a continuous stream of images of a soil stratigraphy at two levels of magnification as the probe is advanced vertically through a soil. The VisCPT delineates soil types and through computer image processing it facilitates very high-resolution stratigraphic characterization of a site. The present research effort will consist of three parts: Development of standard indices for soil grain size based on the power spectra of wavelet-transformed images; Modifications to the existing VisCPT instrumentation including adaptation of color cameras and real-time digital image acquisition; and field data collection at the National Geotechnical Experimentation (NGES) site on Treasure Island in San Francisco. The collected VisCPT data will be evaluated with specific focus on image-texture and wavelet transform techniques for determining soil type. Continuous high quality piston tube soil samples will be taken for comparison to VisCPT results. The VisCPT images will also be compared to standard piezocone (uCPT) test results to illustrate and quantify the effects of thin strata on uCPT readings. It is anticipated that the modifications to the VisCPT will substantially enhance the ability of geotechnical engineers to characterize a site, especially with regard to the identification and location of thin strata. This will lead to significant improvement in predictions of liquefaction potential, settlement rates and other critical behaviors.